Polishing pad conditioning system and method of using

ABSTRACT

A method of conditioning a polishing pad includes conditioning the polishing pad using a conditioner. The method includes detecting a roughness of the polishing pad following the conditioning. The method further includes tracking a number of iterations of the conditioning of the polishing pad. The method further includes outputting a signal for replacing the polishing pad in response to the number of iterations reaching an iteration limit. The method further includes repeating the conditioning in response to the detected roughness of the polishing pad being outside of a threshold roughness range and the number of iterations failing to reach the iteration limit.

PRIORITY CLAIM

The present application is a continuation of U.S. application Ser. No.16/910,978, filed Jun. 24, 2020, which claims priority to the ChinaPatent Application No. 202010476541.7, filed May 29, 2020, which theentire contents of which are hereby incorporated by reference.

BACKGROUND

Integrated circuits are formed using various processing steps. Someprocessing steps involve depositing dielectric layers or metal layers ona semiconductor wafer. The deposition processes result in non-planarsurfaces, in some instances. The non-planar surfaces are polished toprovide a more uniform surface for additional processing. In someinstances, the polishing is performed by chemical mechanical polishing(CMP) which removes material from the non-planar surfaces to provide themore uniform surface and reduce a thickness of the semiconductor wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a diagram of a chemical mechanical polishing (CMP) system inaccordance with one or more embodiments.

FIG. 2 is a flowchart of a method of using a CMP system in accordancewith one or more embodiments.

FIG. 3 is a block diagram of a computing device for controlling a CMPsystem in accordance with one or more embodiments.

FIGS. 4A and 4B are cross sectional views of a polishing pad and a waferin accordance with one or more embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components, values, operations, materials,arrangements, or the like, are described below to simplify the presentdisclosure. These are, of course, merely examples and are not intendedto be limiting. Other components, values, operations, materials,arrangements, or the like, are contemplated. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Chemical mechanical polishing (CMP) is used to planarize a surface of asemiconductor device during processing. Ideally, following a CMP processthe surface of the semiconductor device is completely flat. However,multiple factors impact the performance of a CMP process during amanufacturing process. One of those factors is roughness of thepolishing pad. Roughness of the polishing pad will impact polishingbehavior of the CMP process based on different pattern densities. Apattern density is a density of features on a surface of a wafer. As thenumber of features per unit area increases, the pattern density alsoincreases. In some instances, as a roughness of the polishing paddecreases below a threshold range, a ratio of a thickness for a lowdensity area and a thickness for a high density area decreases to beless than a target range. For example, FIG. 4B includes a polishing padhaving a roughness below the threshold range. Conversely, in someinstances, as a roughness of the polishing pad increases to be above thethreshold range, the ratio of the thickness for the low density area andthe thickness for the high density area increases to above the targetrange. For example, FIG. 4A includes a polishing pad having a roughnessabove the threshold range. That is, a polishing pad having a surfaceroughness outside of the threshold range results in thickness variationacross the wafer depending on the location of high pattern densityregions and low pattern density regions.

According to some embodiments of the current description, monitoring theroughness of the polishing pad and controlling a pad conditioningprocess helps to reduce or avoid thickness variations across the waferby controlling the polishing pad roughness to be within the thresholdrange. In some embodiments, a number of iterations of a conditioningprocess is controlled to help manage the polishing pad roughness. Insome embodiments, a number of conditioning pads utilized in aconditioning process is controlled to help manage the polishing padroughness. In some embodiments, a pressure or location of theconditioning pad is controlled to help manage the polishing padroughness. By controlling the conditioning process, the roughness of thepolishing pad is maintained within a threshold range.

As a polishing pad continues to polish wafers, the polishing pad iseventually degraded to the point where the polishing pad is no longerable to be restored to a roughness in the threshold range. If thepolishing pad is replaced too often, then the cost of manufacturingincreases because usable polishing pads are being replaced prematurely.In contrast, if the polishing pad is replaced too late, then wafersundergoing the CMP process using a polishing pad that should have beenreplaced will have increased thickness variation. As a result, thechances of the devices formed on the wafer being faulty increases. Insome embodiments, a controller is used to determine when to replace thepolishing pad in order to help reduce manufacturing costs and to reducethe risk of faulty devices on the wafer.

A CMP system uses a combination of chemical reactions and mechanicalgrinding to remove material from a surface of a semiconductor device.FIG. 1 is a diagram of a CMP system 100 in accordance with one or moreembodiments. CMP system 100 includes a platen 102 configured to rotatein at least one direction. A polishing pad 104 is provided on top ofplaten 102. A polishing head 106 is configured to support a wafer forprocessing using CMP system 100. Polishing head 106 is configured toadjust a pressure exerted on the wafer by polishing pad 104. CMP system100 further includes a conditioner 108 configured to restore a roughnessof polishing pad 104. CMP system 100 further includes a slurry deliverysystem 110 configured to deliver a slurry to polishing pad 104 tofacilitate removal of material from the wafer. A sensor 115 is used tomonitor the roughness of polishing pad 104. An optional sensor 117 isconfigured to receive light reflected from sensor 115, in someembodiments. A controller 120 is configured to receive information fromsensor 115 or sensor 117 and to control conditioner 108 based on thereceived information.

CMP system 100 removes material from the wafer based on relative motionbetween polishing pad 104 and polishing head 106. A slurry introduced topolishing pad 104 by slurry delivery system 110 reacts with materials onthe wafer and mechanical force exerted on the wafer by the polishing padremoves material from the wafer.

Platen 102 is configured to rotate in at least a first direction. Insome embodiments, platen 102 is configured to rotate in more than onedirection. In some embodiments, platen 102 is configured to be heldstationary. In some embodiments, platen 102 is configured to have aconstant rotational speed. In some embodiments, platen 102 is configuredto have a variable rotational speed. In some embodiments, platen 102 isrotated by a motor. In some embodiments, the motor is an alternatingcurrent (AC) motor, a direct current (DC) motor, a universal motor, oranother suitable motor. In some embodiments, platen 102 is configured totranslate in one or more directions.

Platen 102 is configured to support polishing pad 104. Polishing pad 104is configured to connect to platen 102 so that polishing pad 104 rotatesin a same direction at a same speed as the platen. In some embodimentswhere platen 102 is stationary, polishing pad 104 is held stationary.Polishing pad 104 has a textured surface which is configured to removematerial from the wafer during operation of CMP system 100.

Polishing head 106 is configured to support the wafer during operationof CMP system 100. In some embodiments, polishing head 106 includes aretaining ring to secure the wafer against the polishing head. In someembodiments, polishing head 106 includes a vacuum to secure the waferagainst the polishing head. Polishing head 106 is configured to rotatein a second direction. In some embodiments, the second direction is thesame as the first direction. In some embodiments, the second directionis opposite the first direction. In some embodiments, polishing head 106is configured to rotate at a constant rotational speed. In someembodiments, polishing head 106 is configured to rotate at a variablerotational speed. In some embodiments, polishing head 106 is rotated bya motor. In some embodiments, the motor is an AC motor, a DC motor, auniversal motor, or another suitable motor. In some embodiments,polishing head 106 is held stationary. In some embodiments, polishinghead 106 translates relative to polishing pad 104.

Polishing head 106 is configured to move in a direction perpendicular tothe surface of polishing pad 104. By moving polishing head 106 in thedirection perpendicular to the surface of polishing pad 104, thepressure exerted on the wafer by the polishing pad is adjustable. Insome embodiments, polishing head 106 includes pressure sensors tomonitor a pressure exerted on the wafer. In some embodiments, thepressure sensors are connected to a control system. In some embodiments,polishing head 106 includes pressure adjustment devices configured toexert force on a surface of wafer opposite polishing pad 104 to adjustthe pressure exerted on the wafer at various locations of the wafer. Insome embodiments, the pressure adjustment devices include nozzlesconfigured to emit pressurized gas, translatable pins or other suitableforce exerting elements.

Conditioner 108 is configured to restore the roughness of polishing pad104. During operation of CMP system 100, a roughness of polishing pad104 decreases as a result of the force between the wafer and thepolishing pad or through a buildup of slurry or other particles.Conditioner 108 is configured to restore the roughness of polishing pad104 to maintain effective operation of CMP system 100.

Conditioner 108 includes a conditioner pad 108 a configured to contactpolishing pad 104. In some embodiments, conditioner pad 108 a isconfigured to rotate. Conditioner 108 also includes a conditioner arm108 b configured to translate conditioner pad 108 a across the surfaceof polishing pad 104.

Slurry delivery system 110 is configured to provide the slurry ontopolishing pad 104. In some embodiments, slurry deliver system 110includes a slurry mixing system configured to mix various fluidcompositions prior to delivering the mixture to polishing pad 104.Slurry delivery system 110 includes at least one nozzle 110 a configuredto deliver the slurry to polishing pad 104. Slurry delivery system 110further includes a delivery arm 110 b configured to translate a locationof nozzle 110 a relative to the surface of polishing pad 104.

Sensor 115 is configured to collect information related to the roughnessof polishing pad 104. A single sensor 115 is included in FIG. 1 forsimplicity. In some embodiments, multiple sensors 115 are included todetect the roughness at different locations on polishing pad 104. Insome embodiments, sensor 115 is an integrated array of sensing elementsextending across a portion of polishing pad 104. By collectinginformation on roughness at different locations, sensors 115 would beable to more precisely locate portions of polishing pad 104 having aroughness outside of a threshold range. In some embodiments, sensor 115is an optical sensor configured to receive light reflected from thesurface of polishing pad 104. In some embodiments, sensor 115 issensitive to visible light. In some embodiments, sensor 115 is sensitiveto infrared (IR) light. In some embodiments, each sensor 115 of multiplesensors 115 is a same type of sensor, e.g., visible light detectingsensor. In some embodiments, at least one sensor 115 of multiple sensors115 is different from another sensor 115, e.g., one sensor 115 issensitive to visible light and one sensor 115 is sensitive to IR light.In some embodiments, sensor 115 is configured to emit light towardpolishing pad 104.

Sensor 117 is configured to receive light originating from sensor 115that is reflected by polishing pad 104. A single sensor 117 is includedin FIG. 1 for simplicity. In some embodiments, multiple sensors 117 areincluded to detect the roughness at different locations on polishing pad104. In some embodiments, sensor 117 is an integrated array of sensingelements extending across a portion of polishing pad 104. By collectinginformation on roughness at different locations, sensors 117 would beable to more precisely locate portions of polishing pad 104 having aroughness outside of a threshold range. In some embodiments, each sensor115 is paired with a sensor 117. In some embodiments, at least onesensor 115 is a stand-alone sensor that is not paired with a sensor 117.In some embodiments, sensor 117 is an optical sensor configured toreceive light reflected from the surface of polishing pad 104. In someembodiments, sensor 117 is sensitive to visible light. In someembodiments, sensor 117 is sensitive to IR light. In some embodiments,each sensor 117 of multiple sensors 117 is a same type of sensor, e.g.,visible light detecting sensor. In some embodiments, at least one sensor117 of multiple sensors 117 is different from another sensor 117, e.g.,one sensor 117 is sensitive to visible light and one sensor 117 issensitive to IR light. In some embodiments, sensor 117 is omitted whereevery sensor 115 is a stand-alone sensor.

Polishing pad 104 has a radius R extending from the center of the platento an exterior edge of the platen. In some embodiments, radius R ofpolishing pad 104 is at least 2.5 times greater than a radius ofpolishing head 106. If the radius R of polishing pad 104 is less thanthe 2.5 times greater than the radius of polishing head 106, maintaininga roughness of the polishing pad will be difficult, which increasespolishing time and decreases production yield, in some embodiments.

As polishing pad 104 and polishing head 106 rotate, a location ofdetection point(s) for sensor 115 and/or sensor 117 relative to thepolishing pad 104 changes. By using multiple distinct detection points,a more uniform amount of data is collected related to various areasacross polishing pad 104. The uniform amount of data enables a moreaccurate determination of a roughness profile of polishing pad 104. Aroughness profile is a variation of roughness across the surface ofpolishing pad 104. For example, in some embodiments, a region of thepolishing pad 104 used most often during the CMP process will have alowest roughness in some instances.

Controller 120 is configured to receive information from sensor 115. Insome embodiments which include sensor 117, controller 120 is configuredto receive information from sensor 117. In some embodiments, theinformation includes an image of the polishing pad 104. In someembodiments, the information includes a signal indicating a roughness ofthe polishing pad 104. Controller 120 is configured to determine aroughness of polishing pad 104 based on the received information. Insome embodiments including multiple sensors 115 and/or sensors 117,controller 120 is configured to determine a roughness profile ofpolishing pad 104.

Based on the information from the sensor 115 or sensor 117 for polishingpad 104, controller 120 is configured to control conditioner 108. Insome embodiments, controller 120 controls a number of iterations of aconditioning process of conditioner 108. Controller 120 is alsoconfigured to track the iterations of a conditioning process used onpolishing pad 104. In some embodiments, controller 120 is configured toadjust the pressure of conditioner head 108 a on polishing pad 104. Insome embodiments, controller 120 is configured to adjust the location ofconditioner head 108 a based on a determined roughness profile ofpolishing pad 104. In some embodiments, controller 120 is configured tocontrol a secondary conditioner (not shown) to increase the number ofconditioners used to adjust the roughness of polishing pad 104.

FIG. 2 is a flowchart of a method 200 of using a CMP system inaccordance with one or more embodiments. In operation 202, a wafer isattached to a polishing head. In some embodiments, the wafer is attachedto polishing head 106 (FIG. 1 ). In some embodiments, the wafer isattached to the polishing head using a retaining ring. In someembodiments, the wafer is attached to the polishing head using a vacuumor other suitable attachment element. In some embodiments, operation 202is omitted. For example, operation 202 is omitted when the operation isimplemented by a user or by another device.

In operation 204, a CMP process is begun. The CMP process comprisesapplying pressure on the wafer against a polishing pad. In someembodiments, the wafer is rotated relative to the polishing pad. In someembodiments, the polishing pad is rotated relative to the wafer. In someembodiments, both the wafer and the polishing pad are rotated. The CMPprocess also includes applying a slurry to the polishing pad andconditioning the polishing pad to restore a texture of the polishingpad. In some embodiments, the wafer is configured to translate relativeto the polishing pad. In some embodiments, the polishing pad isconfigured to translate relative to the wafer. In some embodiments,operation 204 is omitted. For example, operation 204 is omitted when theoperation is implemented by a user or by another device.

In step 206, a roughness of the polishing pad is monitored. In someembodiments, the roughness of the polishing pad is monitored using asingle point of detection. In some embodiments, the roughness of thepolishing pad is monitored using multiple points of detection. In someembodiments, the roughness of the polishing is monitored using sensor115 and/or sensor 117 (FIG. 1 ). In some embodiments, multiple points ofdetection are used to monitor a roughness profile of the polishing pad.In some embodiments, the roughness of the polishing pad is monitoredusing reflected light beams.

In step 208, a conditioner of the CMP system is controlled in order toadjust the roughness of the polishing pad. In some embodiments, a numberof iterations of the conditioning process is adjusted based oninformation received from the sensor, e.g., sensor 115 and/or sensor 117(FIG. 1 ). In some embodiments, a location of a conditioner head, e.g.,conditioner head 108 a (FIG. 1 ), is adjusted based on information fromthe sensor, e.g., sensor 115 and/or sensor 117. In some embodiments, thepressure of a conditioner head, e.g., conditioner head 108 a (FIG. 1 ),is adjusted based on information received from the sensor, e.g., sensor115 and/or sensor 117. In some embodiments, a smooth conditioner is usedto reduce a roughness of the polishing pad. In some embodiments, thepressure of the conditioner head is adjusted by moving the conditionerhead in the direction perpendicular to the polishing pad. In someembodiments, the movement of the conditioner head occurs during a CMPprocess. In some embodiments, the movement of the conditioner headoccurs after the CMP process. In some embodiments, the conditioner isadjusted to provide a uniform profile on a polished surface of thewafer. In some embodiments, an additional conditioner head is usedduring a conditioning process. In some embodiments, the additionalconditioning head helps to reduce an amount of time for completing theconditioning process. In some embodiments, the additional conditionerhead helps to account for variations in the roughness profile in thepolishing pad.

In operation 210, the roughness of the polishing pad is compared with athreshold roughness range. In some embodiments, the threshold roughnessrange is selected by a user. In some embodiments, the thresholdroughness range is determined based on empirical data related toperformance of the CMP processing. In some embodiments, roughnessinformation is collected after the conditioning process to compare withthe threshold roughness range. In some embodiments, the roughnessinformation is collected during the conditioning process. In someembodiments, the roughness is measured at a single location on thepolishing pad. In some embodiments, the roughness is measured atmultiple locations on the polishing pad.

Method 200 returns to operation 202 in response to the roughness of thepolishing pad satisfying the threshold roughness range. In someembodiments, a new wafer is placed on the polishing head in response tomethod 200 returning to operation 202. In some embodiments, a same waferon the polishing head undergoes an additional CMP process in response tomethod 200 returning to operation 202. A decision regarding whether toplace a new wafer on the polishing head is based on whether a desiredthickness of the polished wafer is achieved. Method 200 proceeds tooperation 212 in response to the roughness of the polishing pad failingto satisfy the threshold roughness range. In some embodiments, if theroughness at any single location on the polishing pad fails to satisfythe threshold roughness range, then method 200 proceeds to operation212. In some embodiments, if the roughness of a first location on thepolishing pad fails to satisfy the threshold roughness range, but asecond location satisfies the threshold roughness range, then anadditional iteration of conditioning is performed only on the failedlocations of the polishing pad.

In operation 212, the number of iterations of the conditioning processis compared with an iteration limit. In some embodiments, the iterationlimit ranges from about 3 to about 5 iterations. If the number for theiteration limit is too low, then the polishing pad is replaced morefrequently, which increases production costs in some instances. If thenumber for the iteration limit is too high, then extra time is spentattempting to increase the roughness of the polishing pad which reducesproduction output of the manufacturing process. In some embodiments, thenumber of iterations is adjusted in response to the conditioning processincluding multiple conditioners. For example, in some embodiments, iftwo conditioners are used in the conditioning process, the number ofiterations of the conditioning process is increased by two instead ofone. In some embodiments, the number of iterations of the conditioningprocess is determined without consideration of the number ofconditioners used in the conditioning process. Method 200 returns tooperation 206 in response to the number of iterations being less thanthe iteration limit. Method 200 proceeds to operation 214 in response tothe number of iterations reaching the iteration limit.

In operation 214, the CMP process is stopped. In some embodiments, theCMP process is stopped based on the thickness of the wafer reaching atarget thickness. In some embodiments, the CMP process is stopped basedon a duration of the CMP process reaching a target duration. In someembodiments, the CMP process is stopped based on the roughness of thepolishing pad being unable to properly perform the CMP process.

In operation 216, the polishing pad is replaced. In some embodiments, auser is notified and instructed to replace the polishing pad. In someembodiments, a control signal is transmitted to an automatic system forreplacing the polishing pad; and the automatic system replaces thepolishing pad without user interaction.

In some embodiments, at least one operation is included in method 200prior to the described operations. For example, in some embodiments, aninitial polishing pad is attached to the platen prior to operation 202.In some embodiments, at least one operation is performed after thedescribed operations. For example, in some embodiments, a conditioner isreplaced after the polishing pad is replaced. In some embodiments, atleast one operation from method 200 is omitted. For example, in someembodiments, operation 202 is omitted as described above. In someembodiments, an order of operations of method 200 is altered. Forexample, in some embodiments, operation 208 is performed prior tooperation 206. In some embodiments, when operation 208 is performedprior to operation 206 a default conditioning process is performed in afirst iteration and the conditioning process is adjusted in subsequentiterations based on the detected roughness of the polishing pad.

FIG. 3 is a block diagram of a computing device 300 for controlling aCMP system in accordance with one or more embodiments. Computing device300 includes a hardware processor 302 and a non-transitory, computerreadable storage medium 304 encoded with, i.e., storing, the computerprogram code 306, i.e., a set of executable instructions. Computerreadable storage medium 304 is also encoded with instructions 307 forinterfacing with elements of CMP system 100. The processor 302 iselectrically coupled to the computer readable storage medium 304 via abus 308. The processor 302 is also electrically coupled to an I/Ointerface 310 by bus 308. A network interface 312 is also electricallyconnected to the processor 302 via bus 308. Network interface 312 isconnected to a network 314, so that processor 302 and computer readablestorage medium 304 are capable of connecting to external elements vianetwork 314. The processor 302 is configured to execute the computerprogram code 306 encoded in the computer readable storage medium 304 inorder to cause computing device 300 to be usable for performing aportion or all of the operations as described with respect to CMP system100.

In some embodiments, the processor 302 is a central processing unit(CPU), a multi-processor, a distributed processing system, anapplication specific integrated circuit (ASIC), and/or a suitableprocessing unit.

In some embodiments, the computer readable storage medium 304 is anelectronic, magnetic, optical, electromagnetic, infrared, and/or asemiconductor system (or apparatus or device). For example, the computerreadable storage medium 304 includes a semiconductor or solid-statememory, a magnetic tape, a removable computer diskette, a random accessmemory (RAM), a read-only memory (ROM), a rigid magnetic disk, and/or anoptical disk. In some embodiments using optical disks, the computerreadable storage medium 304 includes a compact disk-read only memory(CD-ROM), a compact disk-read/write (CD-R/W), and/or a digital videodisc (DVD).

In some embodiments, the storage medium 304 stores the computer programcode 306 configured to cause computing device 300 to perform theoperations as described with respect to CMP system 100. In someembodiments, the storage medium 304 also stores information needed forperforming the operations as described with respect to CMP system 100,such as a sensor parameter 316, a conditioning iterations parameter 318,a conditioner pressure parameter 320, a target roughness parameter 322and/or a set of executable instructions to perform the operation asdescribed with respect to CMP system 100.

In some embodiments, the storage medium 304 stores instructions 307 forinterfacing with CMP system 100. The instructions 307 enable processor302 to generate operating instructions readable by elements of the CMPsystem 100 to effectively implement the operations as described withrespect to CMP system 100.

Computer device 300 includes I/O interface 310. I/O interface 310 iscoupled to external circuitry. In some embodiments, I/O interface 310includes a keyboard, keypad, mouse, trackball, trackpad, and/or cursordirection keys for communicating information and commands to processor302.

Computing device 300 also includes network interface 312 coupled to theprocessor 302. Network interface 312 allows computing device 300 tocommunicate with network 314, to which one or more other computersystems are connected. Network interface 312 includes wireless networkinterfaces such as BLUETOOTH, WIFI, WIMAX, GPRS, or WCDMA; or wirednetwork interface such as ETHERNET, USB, or IEEE-1394. In someembodiments, the operations as described with respect to CMP system 100are implemented in two or more computing devices 300, and informationsuch as sensor information, conditioning iterations information,conditioner pressure and target roughness are exchanged betweendifferent computing devices 300 via network 314.

Computing device 300 is configured to receive information related to thesensor, e.g., sensor 115 and/or sensor 117 (FIG. 1 ), through I/Ointerface 310. The information is transferred to processor 302 via bus308 to determine the roughness of the polishing pad at the sensorlocation. The roughness and/or profile are then stored in computerreadable medium 304 as sensor parameter 316. Computing device 300 isconfigured to receive information related to the conditioning iterationsthrough I/O interface 310. The information is transferred to processor302 via bus 308 to determine the number of conditioning iterations. Thenumber of conditioning iterations are then stored in computer readablemedium 304 as conditioning iterations parameter 318. Computing device300 is configured to receive information related to conditioner pressurethrough I/O interface 310. In some embodiments, the pressure informationis provided by pressure sensors located in the conditioning head. Theinformation is stored in computer readable medium 304 as conditionerpressure parameter 320. Computing device 300 is configured to receiveinformation related to target roughness through I/O interface 310. Insome embodiments, the target roughness information is received from anoperator. In some embodiments, the target roughness is calculated basedon information received by computing device 300 related to amanufacturing process. The information is stored in computer readablemedium 304 as target roughness parameter 322.

During operation, in some embodiments, processor 302 executes a set ofinstructions to determine whether to perform another iteration of aconditioning process using the conditioner based on sensor parameter316, conditioning iterations parameter 318 and target roughnessparameter 322. During operation, processor 302 executes a set ofinstructions to determine whether the roughness of the polishing pad iswithin a threshold range based on sensor parameter 316 and targetroughness parameter 322. Based on the above determinations, processor302 generates a control signal to instruct the conditioner to performanother conditioning process. In some embodiments, the control signal istransmitted using I/O interface 310. In some embodiments, the controlsignal is transmitted using network interface 312.

During operation, in some embodiments, processor 302 executes a set ofinstructions to determine whether to adjust the pressure of theconditioner based on sensor parameter 316, conditioner pressureparameter 320 and target roughness parameter 322. During operation,processor 302 executes a set of instructions to determine whether theroughness of the polishing pad is within a threshold range based onsensor parameter 316 and target roughness parameter 322. Based on theabove determinations, processor 302 generates the pressure adjustmentsignal to adjust the position of the conditioner head. In someembodiments, the pressure adjustment signal is transmitted using I/Ointerface 310. In some embodiments, the pressure adjustment signal istransmitted using network interface 312.

During operation, in some embodiments, processor 302 executes a set ofinstructions to determine whether to adjust the location of theconditioner based on sensor parameter 316 and target roughness parameter322. During operation, processor 302 executes a set of instructions todetermine whether the roughness of the polishing pad is within athreshold range at various locations across the polishing pad based onsensor parameter 316 and target roughness parameter 322. Based on theabove determinations, processor 302 generates conditioner locationadjustment signal to adjust the position of the conditioner head on thepolishing pad. The position of the conditioner head is adjustable in adirection perpendicular to the polishing pad to adjust the pressureexerted on the polishing pad; or in a direction parallel to a topsurface of the polishing pad to condition a different zone of thepolishing pad. In some embodiments, the conditioner location adjustmentsignal is transmitted using I/O interface 310. In some embodiments, theconditioner location adjustment signal is transmitted using networkinterface 312.

An aspect of this description relates to a method of conditioning apolishing pad. The method includes conditioning the polishing pad usinga conditioner. The method includes detecting a roughness of thepolishing pad following the conditioning. The method further includestracking a number of iterations of the conditioning of the polishingpad. The method further includes outputting a signal for replacing thepolishing pad in response to the number of iterations reaching aniteration limit. The method further includes repeating the conditioningin response to the detected roughness of the polishing pad being outsideof a threshold roughness range and the number of iterations failing toreach the iteration limit. In some embodiments, the method furtherincludes beginning a chemical mechanical polishing (CMP) process. Insome embodiments, the method further includes stopping the CMP processin response to the number of iterations reaching the iteration limit. Insome embodiments, conditioning the polishing pad includes rotating theconditioner relative to the polishing pad. In some embodiments,conditioning the polishing pad includes translating the conditioneracross the polishing pad. In some embodiments, detecting the roughnessof the polishing pad includes detecting the roughness of the polishingpad using a plurality of sensors, wherein each sensor of the pluralityof sensors is at a different location relative to the polishing pad. Insome embodiments, detecting the roughness of the polishing pad includesdetecting the roughness of the polishing pad using visible light andinfrared light. In some embodiments, detecting the roughness of thepolishing pad includes detecting the roughness of the polishing pad at aplurality of locations on the polishing pad. In some embodiments, theiteration limit ranges from 3 to 5.

An aspect of this description relates to a method of conditioning apolishing pad. The method includes detecting a roughness of thepolishing pad. The method further includes tracking a number ofiterations of conditioning of the polishing pad. The method furtherincludes determining whether the detected roughness satisfies aroughness threshold. The method further includes determining whether thenumber of iterations is equal to or greater than an iteration limit inresponse to determining that the detected roughness fails to satisfy theroughness threshold. The method further includes outputting a signal forreplacing the polishing pad in response to the number of iterationsbeing equal to or greater than the iteration limit and the detectedroughness failing to satisfy the roughness threshold. In someembodiments, the method further includes performing a chemicalmechanical polishing (CMP) process in response to the detected roughnesssatisfying the roughness threshold. In some embodiments, performing theCMP process includes performing the CMP process regardless of the numberof iterations. In some embodiments, the method further includes stoppingthe CMP process in response to the number of iterations being equal toor greater than the iteration limit and the detected roughness failingto satisfy the roughness threshold. In some embodiments, the methodfurther includes conditioning the polishing pad using a conditioner. Insome embodiments, the method further includes repeating the conditioningin response to the detected roughness of the polishing pad being failingto satisfy the roughness threshold roughness and the number ofiterations being less than the iteration limit.

An aspect of this description relates to a system for controlling apolishing pad. The system includes a non-transitory computer readablemedium configured to store instructions thereon. The system furtherincludes a processor connected to the non-transitory computer readablemedium. The processor is configured to execute the instructions fordetecting a roughness of the polishing pad. The processor is furtherconfigured to execute the instructions for tracking a number ofiterations of conditioning of the polishing pad. The processor isfurther configured to execute the instructions for determining whetherthe detected roughness satisfies a roughness threshold. The processor isfurther configured to execute the instructions for determining whetherthe number of iterations is equal to or greater than an iteration limitin response to determining that the detected roughness fails to satisfythe roughness threshold. The processor is further configured to executethe instructions for outputting a signal for replacing the polishing padin response to the number of iterations being equal to or greater thanthe iteration limit and the detected roughness failing to satisfy theroughness threshold. In some embodiments, the system further includes aplurality of sensors, wherein the processor is configured to execute theinstructions for detecting the roughness of the polishing pad based onan output of each of the plurality of sensors. In some embodiments, afirst sensor of the plurality of sensors is configured to detect lighthaving a first wavelength, and a second sensor of the plurality ofsensors is configured to detect light having a second wavelengthdifferent from the first wavelength.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method of conditioning a polishing padcomprising: conditioning the polishing pad using a conditioner;detecting a roughness of the polishing pad following the conditioning;tracking a number of iterations of the conditioning of the polishingpad; outputting a signal for replacing the polishing pad in response tothe number of iterations reaching an iteration limit; and repeating theconditioning in response to the detected roughness of the polishing padbeing outside of a threshold roughness range and the number ofiterations failing to reach the iteration limit.
 2. The method of claim1, further comprising beginning a chemical mechanical polishing (CMP)process.
 3. The method of claim 2, further comprising stopping the CMPprocess in response to the number of iterations reaching the iterationlimit.
 4. The method of claim 1, wherein conditioning the polishing padcomprises rotating the conditioner relative to the polishing pad.
 5. Themethod of claim 1, wherein conditioning the polishing pad comprisestranslating the conditioner across the polishing pad.
 6. The method ofclaim 1, wherein detecting the roughness of the polishing pad comprisesdetecting the roughness of the polishing pad using a plurality ofsensors, wherein each sensor of the plurality of sensors is at adifferent location relative to the polishing pad.
 7. The method of claim1, wherein detecting the roughness of the polishing pad comprisesdetecting the roughness of the polishing pad using visible light andinfrared light.
 8. The method of claim 1, wherein detecting theroughness of the polishing pad comprises detecting the roughness of thepolishing pad at a plurality of locations on the polishing pad.
 9. Themethod of claim 1, wherein the iteration limit ranges from 3 to
 5. 10. Amethod of conditioning a polishing pad comprising: detecting a roughnessof the polishing pad; tracking a number of iterations of conditioning ofthe polishing pad; determining whether the detected roughness satisfiesa roughness threshold; determining whether the number of iterations isequal to or greater than an iteration limit in response to determiningthat the detected roughness fails to satisfy the roughness threshold;and outputting a signal for replacing the polishing pad in response tothe number of iterations being equal to or greater than the iterationlimit and the detected roughness failing to satisfy the roughnessthreshold.
 11. The method of claim 10, further comprising performing achemical mechanical polishing (CMP) process in response to the detectedroughness satisfying the roughness threshold.
 12. The method of claim11, wherein performing the CMP process comprises performing the CMPprocess regardless of the number of iterations.
 13. The method of claim11, further comprising stopping the CMP process in response to thenumber of iterations being equal to or greater than the iteration limitand the detected roughness failing to satisfy the roughness threshold.16. The method of claim 10, further comprising conditioning thepolishing pad using a conditioner.
 17. The method of claim 16, furthercomprising repeating the conditioning in response to the detectedroughness of the polishing pad being failing to satisfy the roughnessthreshold roughness and the number of iterations being less than theiteration limit.
 18. A system for controlling a polishing pad,comprising: a non-transitory computer readable medium configured tostore instructions thereon; and a processor connected to thenon-transitory computer readable medium, wherein the processor isconfigured to execute the instructions for: detecting a roughness of thepolishing pad; tracking a number of iterations of conditioning of thepolishing pad; determining whether the detected roughness satisfies aroughness threshold; determining whether the number of iterations isequal to or greater than an iteration limit in response to determiningthat the detected roughness fails to satisfy the roughness threshold;and outputting a signal for replacing the polishing pad in response tothe number of iterations being equal to or greater than the iterationlimit and the detected roughness failing to satisfy the roughnessthreshold.
 19. The system of claim 18, further comprising a plurality ofsensors, wherein the processor is configured to execute the instructionsfor detecting the roughness of the polishing pad based on an output ofeach of the plurality of sensors.
 20. The system of claim 19, wherein afirst sensor of the plurality of sensors is configured to detect lighthaving a first wavelength, and a second sensor of the plurality ofsensors is configured to detect light having a second wavelengthdifferent from the first wavelength.